no-state dispatch-only connected components

One common misunderstanding in the react redux ecosystem is the meaning of connected component, for many a connected component is a component that is connected to the redux store state, but as dan Abramov see it, a connected component is connected to redux, not just it’s state.

Think of connect as “connect to Redux” and not just “connect to a part of Redux state”. — Dan Abramov

That means state is available to a connected component if needed but this is not mandatory, infact you can connect a component without subscribing to the store changes.

https://github.com/reactjs/react-redux/blob/master/src/components/connect.js#L36

A great scenario for that is an action button, think about a list of hundreds of cards with a toolbar on each one, having all these component subscribed to store changes might be costly, fortunately if you pass null as as mapStateToProps inside the connect Higher order component from react-redux, the component will have access to dispatch method without subscribing to the store.

I encourage you to dig into react-redux source code as it is actually very small and well documented.